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Spin transport phenomena in Dirac magnets and their applications for spintronics

Research Project

Project/Area Number 19K22124
Research Category

Grant-in-Aid for Challenging Research (Exploratory)

Allocation TypeMulti-year Fund
Review Section Medium-sized Section 29:Applied condensed matter physics and related fields
Research InstitutionThe University of Tokyo

Principal Investigator

Shiomi Yuki  東京大学, 大学院総合文化研究科, 准教授 (10633969)

Project Period (FY) 2019-06-28 – 2021-03-31
Project Status Completed (Fiscal Year 2020)
Budget Amount *help
¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000)
Fiscal Year 2020: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Fiscal Year 2019: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
Keywordsディラック磁性体 / スピントロニクス / スピンホール効果 / トポロジー / ベリー位相 / トポロジカル磁性体 / 磁性薄膜
Outline of Research at the Start

スピントロニクス素子において必要となる高効率なスピン流-電流変換素子材料の新開発指針として、新しいトポロジカル磁性体である「ディラック磁性体」を提案する。歪みを印加した際の特異なバンド構造に由来するトポロジー効果により発現することが期待される、高効率なスピンホール効果の実証を狙う。

Outline of Final Research Achievements

We mainly focused on thin films of γ-phase FeMn, which is a candidate for Dirac magnets. In γ-FeMn, a spin-degenerate Dirac cone was predicted near the Fermi level under a tight-binding approximation, and it was predicted that a spin Hall effect shows up due to strain. We prepared FeMn/Ni-Fe thin films on a piezoelectric substrate and annealed them under the presence of strain and an external magnetic field. For these samples, we measured spin Seebeck/anomalous Nernst effects at room temperature to estimate the magnitude of the spin Hall effect. However, evidence of the spin Hall effect was not obtained within the measurement accuracy. On the other hand, a large exchange bias effect was observed in the measured thermoelectric signals, and its magnitude is found to be as large as the maximum value reported so far in this bilayer system.

Academic Significance and Societal Importance of the Research Achievements

本研究ではスピントロニクス材料として新しい種類のトポロジカル磁性体である「ディラック磁性体」を提案した。近年スピン縮退の解けた線形バンドの交差点であるワイル点を有する特異な電子構造に由来した高効率なスピン流と電流の変換効果(スピンホール効果)が注目を集めている。一方、本研究ではスピン縮退した線形バンドが交差するディラック点を有する磁性体をディラック磁性体と定義し、その機能開発を行った。特に、歪みの印加により発生すると期待される、ディラック点のベリー位相磁場の効果によるスピンホール効果を観測することを目指して研究を行った。

Report

(3 results)
  • 2020 Annual Research Report   Final Research Report ( PDF )
  • 2019 Research-status Report
  • Research Products

    (6 results)

All 2020 2019

All Journal Article (6 results) (of which Peer Reviewed: 6 results,  Open Access: 2 results)

  • [Journal Article] Enhanced Thermopower in the Antiferromagnetic Phase of Mn2-xCrxSb2020

    • Author(s)
      Nakagawa Kurea、Miyazaki Yu、Mitsuishi Natsuki、Sakano Masato、Yokouchi Tomoyuki、Ishizaka Kyoko、Shiomi Yuki
    • Journal Title

      Journal of the Physical Society of Japan

      Volume: 89 Issue: 12 Pages: 124601-124601

    • DOI

      10.7566/jpsj.89.124601

    • NAID

      40022438255

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Modulation of Dirac electrons in epitaxial Bi2Se3 ultrathin films on van der Waals ferromagnet Cr2Si2Te62020

    • Author(s)
      Kato Takemi、Sugawara Katsuaki、Ito Naohiro、Yamauchi Kunihiko、Sato Takumi、Oguchi Tamio、Takahashi Takashi、Shiomi Yuki、Saitoh Eiji、Sato Takafumi
    • Journal Title

      Physical Review Materials

      Volume: 4 Issue: 8 Pages: 84202-84202

    • DOI

      10.1103/physrevmaterials.4.084202

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Large Magneto-piezoelectric Effect in EuMnBi2 Single Crystal at Low Temperatures2020

    • Author(s)
      Yuki Shiomi, Hidetoshi Masuda, Hidefumi Takahashi, Shintaro lshiwata
    • Journal Title

      Scientific Reports

      Volume: 10 Issue: 1 Pages: 7574-7574

    • DOI

      10.1038/s41598-020-64530-2

    • Related Report
      2020 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Enhanced magnetopiezoelectric effect at the Neel temperature in CaMn2Bi22019

    • Author(s)
      Shiomi Y.、Koike Y.、Abe N.、Watanabe H.、Arima T.
    • Journal Title

      Physical Review B

      Volume: 100 Issue: 5 Pages: 054424-054424

    • DOI

      10.1103/physrevb.100.054424

    • Related Report
      2019 Research-status Report
    • Peer Reviewed
  • [Journal Article] Magnon Pairs and Spin-Nematic Correlation in the Spin Seebeck Effect2019

    • Author(s)
      Hirobe Daichi、Sato Masahiro、Hagihala Masato、Shiomi Yuki、Masuda Takatsugu、Saitoh Eiji
    • Journal Title

      Physical Review Letters

      Volume: 123 Issue: 11 Pages: 117202-117202

    • DOI

      10.1103/physrevlett.123.117202

    • Related Report
      2019 Research-status Report
    • Peer Reviewed
  • [Journal Article] Magnetotransport properties of magnetite-hematite composite oxides2019

    • Author(s)
      Nakagawa K.、Asano H.、Miyazaki Y.、Shiomi Y.
    • Journal Title

      Journal of Applied Physics

      Volume: 126 Issue: 18 Pages: 183904-183904

    • DOI

      10.1063/1.5129079

    • Related Report
      2019 Research-status Report
    • Peer Reviewed

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Published: 2019-07-04   Modified: 2022-01-27  

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